A dementia clinic was maintained to evaluate patients for in- patient and out-patient protocols. One hundred and fifty-five patients were diagnosed with various batteries as having primary degenerative dementia, multi-infarct vascular from non-vascular dementias, whereas other dementias scores were not discriminatory. Pedigrees were constructed from family history of all patients participating in the dementia program, to examine the genetic basis of Alzheimer's disease. Collaborative studies were established to examine the ability of peripheral blood lymphocytes of probands with Down Syndrome and familial Alzheimer's disease to repair X-irradiation induced damage during the G2 period of the cell cycle, and for the Down Syndrome subjects, to see if the parents' lymphocytes show chromosomal instability. Efforts continue to evaluate genetic aspects of presenile dementia. Specifically secondary sex chromosomal variation and alpha-1-antitrypsin (PI) phenotyping and cytological analysis of variations in the Nucleolus Organizing Regions (NOR) were analyzed.